any way to tell at runtime whether a callable is implemented in Python or C ?

Chris Angelico rosuav at
Fri Sep 26 10:42:39 CEST 2014

On Fri, Sep 26, 2014 at 5:47 PM, Wolfgang Maier
<wolfgang.maier at> wrote:
> Hi,
> is there any reliable and inexpensive way to inspect a callable from running
> Python code to learn whether it is implemented in Python or C before calling
> into it ?

I'm not sure you can say for absolute certain, but the presence of a
__code__ attribute is strongly suggestive that there's Python code
behind the function. That might be good enough for your purposes.


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